The present invention relates to a printed wiring board structure for an electronic device and, more particularly, to a printed wiring board structure for a transceiver unit using a flexible printed wiring board.
In a conventional printed wiring board structure for an electronic device, as shown in FIG. 8, a transmitter 5 and a receiver 6 are respectively arranged on two printed wiring boards 1a and 1b, and the printed wiring boards 1a and 1b are arranged such that their surfaces on which parts 3 are not mounted are in contact with each other. A shield case 7 is arranged around them to electrically shield the interior of the device from the external space.
In Japanese Utility Model Laid-Open No. 62-112171 (FIG. 4) and Japanese Patent Laid-Open No. 62-155585, the following example is shown and described. That is, a printed wiring board structure for an electronic device is partially constituted by a flexible printed wiring board, and is stereoscopically assembled to cause its part-mounted surface to face the inside.
However, in the conventional structure shown in FIG. 8, since the parts 3 on the printed wiring boards 1a and 1b have various heights, a space above the short parts 3 is wasted when the shield case 7 is arranged to constitute the stereoscopic structure. For this reason, the device disadvantageously increases in volume.
In addition, the shield case 7 is undesirably required to electrically shield the printed wiring boards 1a and 1b from the external space.
In the latter prior art in which the stereoscopic structure is constituted to cause the part-mounted surface to face inside, coupling disadvantageously occurs between the opposing part-mounted surfaces. This problem is conspicuous in a high-frequency device. This device cannot be constituted without solving the problem.